Group 4 - Gene Expression Teachable Unit: Transcription Teachable Tidbit: Gene expression in the...
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Transcript of Group 4 - Gene Expression Teachable Unit: Transcription Teachable Tidbit: Gene expression in the...
Group 4 - Gene Expression
Teachable Unit: Transcription
Teachable Tidbit: Gene expression in the time of cholera: what’s in the water?
Berenice Aguilar, Brian Couch, Michael Gustin, Kathleeen Matthews, Kate Mouzakis, Dereth Phillips, Les Sommerville, Terri Stoner
http://www.nytimes.com/video/2012/03/31/world/americas/100000001463594/cholera-grips-haiti.html
What are the molecular events leading to cholera toxin gene expression?
Vibrio cholerae toxin protein
2 minute brainstorm
Cholera is caused by the expression of a toxic protein (toxin) produced by the Vibrio cholerae bacteria
What is the first step in gene expression to produce the cholera toxin protein?
Learning Goal:1. Students will understand how changes in the protein/DNA
interface affect transcription
5’toxin mRNA
Learning Outcomes:1. Predict how changes in the protein/DNA interface affect
transcription2. Predict and explain how molecular changes contribute to
cholera toxin production
5’toxin mRNA
Predict and explain why this change in promoter can cause these results?
V. cholerae
straintoxin
promoter sequencetranscription
of toxin mRNAtoxin
proteinproduction
1 GAACTTTCTCG ON +
2 GAACGTTCTCG OFF -
TranscriptionON
Sigma Factor
Promoter
Mutant Promoter
Sigma Factor
TranscriptionOFF
Strain 1
Strain 2
Transcription initiation
V. cholerae
straintoxin
promoter sequencetranscription
of toxin mRNAtoxin
proteinproduction
1 GAACTTTCTCG ON +
2 GAACGTTCTCG OFF -
3 GAACTTTCTCG OFF -
Predict and explain what other factor involved in transcription initiation could give strain 3’s results
TranscriptionON
Sigma Factor
Promoter
Mutant Promoter
Sigma Factor
TranscriptionOFF
Strain 1
Strain 2
Transcription initiation
TranscriptionOFF
MutantSigma Factor
Promoter
Strain 3
Vibriocholerae
StrainToxin promoter
sequenceTranscription of
toxin mRNAToxin
proteinproduction
1 GAACTTTCTCG ON +
2 GAACGTTCTCG OFF -
2* GAACGTTCTCG ON +
Vibrio cholerae strain 2 rapidly mutates to strain 2*. Propose a likely mechanism consistent with your knowledge of protein-DNA interactions (1/2 page, written or drawn, complete and clear)
For your homework (summative assessment)
Learning Goal:1. Students will understand how changes in the protein/DNA
interface affect transcription
Learning Outcomes:1. Predict how changes in the protein/DNA interface affect
transcription2. Predict and explain how molecular changes contribute to
cholera toxin production
5’Toxin mRNA